Torsion spring pressure indicator



May 3, 1955 H. J. GROVER 2,707,397

TORSION SPRING PRESSURE INDICATOR Filed May 17, 1954 2 Sheets-Sheet 1 F/INVENTOR,

HORACE J. GROVE/i.

ATTORNEY y 3, 1955 H. J. GROVER 2,707,397

TORSION SPRING PRESSURE INDICATOR Filed May 17, 1954 2 Sheets-Sheet 2 II I I p a I p I I 4 INVENTOR, HORACE J. GROVE/Z ATTORNEY United StatesPatent TOR-SIGN SPRING PRESSURE INDICATOR Horace J1. Grover,Columbuafihio, assignor to the United States of America as representedby the Secretary of the Army Application May 17, 1954, Serial No.430,466

8 Claims. (Cl. 73.--386) The invention relates to a device of thecharacter named especially applicable to use in barometers and it aimsto present a novel construction in the mounting of a torsion spring andits coordination with aneroid capsules to the end that materials ofexceptional high elastic modulus and low mechanicalstrength-particularly quartz-rnay be used more effectively. Itispossible that some composition of glass or ceramic may be used, but itis well known that metal elements exhibit relatively large errors, dueto. an: elasticity or undesirable thermal response.

A further aim is to present a novel means forintegrating: the variouspressures sensed by the device and to en able improved response to veryslight variations in pressure, so that these may be readily calibratedin values of elevation above sea level, or atmospheres, or otherwise.

A further important aim is to enable the production with. ease of adevice having the advantages set forth, from: readily available stockmaterials with a minimum requirement for special fabrication procedures,and enabling assembly of the device effectively without requiringexceptional skill in the instrument art. A- further important aim is topresent a construction which may be readily dissernbled and repairedwithout requiring special jigs, so that it may be maintainedsatisfactorily by field personnel in remote locations.

Additional objects, advantages and features of inven- 7 tion reside inthe construction arrangement and combinationof parts involved in theembodiment of the invention, as may be understood from the followingdescription and accompanying drawings, wherein Fig. 1 is an isometricperspective, partly in vertical section, of an apparatus embodying theinvention, with portions broken away to disclose internal elements;

Fig. 2 is a fragmentary vertical section at the top of the. stand pipe;

Fig. 3. is a fragmentary vertical sectional view in a plane on the axisof one of the bellows;

Fig. 4 is a fragmentary section in the plane of Fig. 3 illustrating amodification of the connection between the bellows and rocking. lever;

Fig. 5 is a view like Fig. 2, illustrating a modification of theanchorage for the T-head of the torsion spring rod, including adjustingmeans to rotate the T-head in case of need in compensating for, orcorrecting departures of the rocking lever from proper position;

Fig. 6 is a cross section on the line 6-6 of Fig. 5, looking upward;

Fig. 7 is a perspective view of the rotatable anchor block of Fig. 5;

Fig. 8 is a fragmentary vertical section at the right hand. side wall ofthe casing, at the plug 36, of a modified bellows mounting;

Fig. 9 is an elevation of the casing and modified bellows mounting;

' Fig; 110 is afragmentary perspective view of theindicator on the endof the lever carried by the torsion rod, showing the use of a scalemarking extended as may be required.

2,767,397 Ei'atented May 3, 1955 Referring more particularly to thedrawings, Fig. 1 illustrates a rectangular box-like casing 10, which maybe of metal or other suitable structural material. It may be of variousforms, but in this instance consists of a bottom 11, opposite side walls12, arear wall 13, front wall 14, and a top plate 15. These complete arigid inclosure, which is made hermetic, as will appear, and constitutesan independently pressurized chamber 16, which is preferably eitherevacuated, or filled with a non-hygroscopic and non-corrosive gas.Centrally in the top plate an opening 17 is formed therein, around whichthere is erected a stand pipe 18 of cylindrical form, the flanged base19 of which is welded or soldered to the top plate. A duct connection 13is provided on the stand pipe, which may be connected to a pump, or gassupply, for regulation of pressure. and/or content of the chamber 16.

Upon the bottom 11 there is provided a recessed conical step bearing orsocket bearing 20, in which there is set a needle point pivot bearing 21of a torsion spring rod device 22. formed of quartz, as a rectilinearcylinder, coaxial with, and extending nearly to the top of the standpipe. The upper end of this. rod is provided with a T- head 23, which isfitted slidably in a vertically extending slot 24 of an anchor block 25secured upon the upper end of the tube 18. The slot 24 has parallelsides, and extends vertically above and below the Thread 23- so that thelatter is accommodated slidably between the sides of the slot underexpansion and contraction involved by variations of temperature tovwhich the device may be sub jected. A closure cap 26 is secured upon theblock 25, having a recess 27 therein concentric with the rod 22 andhaving a helical compression spring 23 set therein hearing upon theupper side of the T-head 23, so that the rod 22 is yieldingly confinedby this spring with the needle bearing 21 held in the socket bearing 20.Suitable gaslists 29 are confined between the cap 26 and block 25, andbetween the latter and the upper flanged end 30 of the stand pipe 18,the cap and block being suitably flanged so that they may be securedtogether and to the flange of the pipe by screws 31 as shown.

At its lower part, the rod 22 is provided with a rectilinear cross.lever 32 fixed at right angles to the axis of the rod securely so as totransmit torsional stress to the latter when the lever is rotated on theaxis of the rod. The lever is formed with a rearwardly extending arm 33and a somewhat longer forwardly extending arm 34. The needle bearing 21may be formed. on the lower side of the lever or omitted if it isdesired to suspend the rod by the head 23.

Onthe rear arm 33 a vertical fiat 35 is formed on the left hand side ofthe arm extending from top to bottom or the arm and for a suitabledistance longitudinally and on the arm 34' a similar fiat is formed onthe right hand side of the arm, at and extending the same distanceradially from the rod.

In the left hand and right hand walls or the casing, there are set plugelements 36, havin threaded engagement in the respective walls so thatthe plugs may be adjusted axially, and mounted on the outer ends of theplugs exteriorly of the housing 10, there are respective aneroid bellowsor capsules 37. The bases of the bellows are suitably securedhermetically to an enlarged head plate 38 on the plug, and a flexiblecorrugated elastic metal diaphragm 39 is hermetically connected peripheerally to the bellows and head plate so as to close the inner end of thebellows and seal communication with the housing It). The outer end ofthe bellows is closed conventionally by a disk 40 to which there is,connected an axial rod 41, so that the latter will be moved axially byexpansion or contraction of the bellows. The inner end of the rod 41 isattached centrally to the diaphragm 39.. Also connected to the diaphragmand extending exteriorly oppositely from the rod 41 and slidably throughthe plug 36, there is a push rod 42 having a point bearing 43 at itsextremity engaged against the fiat 35 of the adjacent arm of the lever32.

From the foregoing it will be seen that with the plugs properly adjustedthe push rods 42 will bear against respective arms of the lever fromopposite directions, and that collapsing movement of the bellows willrotate the lever clockwise as viewed from above.

By proper adjustment of the upper end or T-head mounting of the rod,pressure corresponding to sea level will apply tension to the rod tobring it to a zero position which may be utilized as an index of sealevel, or zero elevation, and that as pressure decreases recovery of thetorsion rod 22 from strain is permitted by the push rods to move itslower end in such manner as may be utilized to indicate higher levelsrelative to the earth.

For the purpose of indicating variations of pressure, the front wall 14is formed with a port opening 44 and the adjacent arm 34 is formed witha head 45 having vertical and horizontal cross hairs 46. Formed on anupstanding lug 47 within the port 44 immediately below the head 45 thereis a fiducial mark 48, and if desired, other means may be associatedtherewith in the nature of dial or scale to indicate in stages of heightor pressure movements of the cross hairs under operation of the bellowsconnections previously described.

A transparent cover plate or window plate 49 is secured upon the end ofthe housing so as to close the port 44 and seal the housing.

like members 50 extended below and past the respective arms of thelever, and provided with upwardly extended parts having returned pointbearings 43 to engage against the far flat sides of the lever arms, sothat the arms will be pulled counterclockwise by expansion of thebellows, and in such case the rod mounting would be adjusted so that itis at a minimum tension initially, and expansion of the bellows wouldapply increased stress to the rod causing its rotation at the lower end.The last mentioned construction is shown in Fig. 4.

If desired, conventional means may be provided for rotatably mountingthe upper end of the torsion spring rod 22 so that its stress may beproperly regulated and coordinated with the function of the bellows.Also, conventional means may be provided for adjusting the bellowsmountings along the sides of the housing so that the points of bearingof the push rod points on the lever may be adjusted radially of the rodto coordinate the action of the respective bellows with the stresses inthe rod involved in progressive variations of pressure.

This might be of use in case one bellows or capsule manifests acoefiicient of expansion different from that of the other and oppositeone acting on the lever, or in case both bellows manifest a curve ofthermal expansion which is unsatisfactory, or not coordinated with thestress response of a particular material in the spring element 22.

Figures 5 to 7 illustrate one means for efiecting the rotativeadjustment of the T-head of the torsion rod.

in this case, the stand pipe 18 and torsion spring rod 22 are of thesame structure and mounting as before described. Set in the top of thestand pipe 18 there is a bearing block 51 having a bushing portion 52fitted within the-pipe and receiving the head 23 revolubly therein, thismounting permitting also vertical sliding movement of the head withinthe bushing incident to expansion or contraction of the rod 22. Theupper end of the block 51 is enlarged and secured to the flanged end of:the pipe by screws and ring at 51'. This larger part is formed with acircular bore 53 of larger diameter than the bore of thebushing 52 thusproviding a shoulder 54, upon which there is set a worm gear 55, andengaged revolubly through one side of the block 51 there is a worm 56meshed with the gear 55. This worm is formed with a key tenon 57 at oneend which is extended through a reduced terminal part of a horizontalbore 58 accommodating the worm; and at its opposite end the worm isretained by a screw plug 59 engaged in the end of the bore 58. The tenon57 is angular in section so that it may be rotated by a conventional keyor other device to rotate the gear 55. A cover plate 60 is held upon theblock 51 by suitable screws to retain the gear in place, suitablegaskets being provided at 61 above and below the block 51 to efiectproper sealing. The gear is axially bored to accommodate the spring 28,which is confined by the cover plate so as to press upon the T-head ofthe rod 22.

On the under side of the gear 55 there are formed integral lugs 62having parallel opposed faces receiving the head 23 slidablytherebetween so that the upper end of the torsion rod is anchored by thegear 55, against relative rotation.

The last described adjustable anchor means may be utilized in case localconditions or other causes disturb the registration of the cross hair at46 with the fiducial mark 48, or in case test or special use of theinstrument shows need for such correction.

Figs. 8 and 9 show the mounting of the bellows units so that they may beadjusted radially with respect to the adjacent arms of the lever 32, theconstruction of the bellows units and form and mounting of the torsionrod being unchanged and conforming to any or all of the constructionsbefore described.

In this instance, the wall of the case is formed with a horizontal slot63, and the plug 36 is mounted in a closure plate 64 having a thickenedblock part 65 fitted slidably in the slot, the plate being of adequatedimensions to cover the slot at all adjusted positions of the block inthe slot. The plug 36 is engaged centrally through the block portiton65. A suitable gasket 66 is interposed between the plate and the wall ofthe casing. The upper and lower edge portions of the plate arelongitudinally slotted at 67 to receive mounting screws 68 engaged inthe wall of the casing, so that by loosening these screws the plate maybe moved horizontally to adjust the point bearing of either or both ofthe plunger rods along the arms of the lever as discretion dictates.

The fiducial mark 48 may terminate at a horizontal mark 48' at its upperend, arranged to align with the horizontal line of the cross hair markson the lever end, so as to indicate relation of the arm to apredetermined normal or zero position of the lever in thermal or otherexpansion and contraction of the rod 22 and/ or stand pipe 18 relativelyto each other, in case the rod is suspended by the head 23. The marks.on the lug 48 would thus be in the form of the letter T with thehorizontal line at the top of the lug, although other arrangement ispossible. The cross hair lines on the lever are formed on a face whichmay be approximately normal to the axis of the lever arm, although itmay be extended concentrically with the axis of the rod, and additionalmarks applied to form a scale calibrated in any units which may beproperly indicated by movement of the lever. By conventional uses ofmagnifying lenses (not shown) small variations may be indicated. Fig.10, illustrates at'70 one possible incorporation of such a scale device.

While the rod has been shown as cylindrical, various other crosssectional forms may be employed, to increase the range of movement ofthe lever for given variations in pressure, or for other reasons.

To adjust the plunger element 42' of Fig. 4, it is necessary todisconnect the anchorage at the top of the rod from the tube 18 andraise the rod, so as to bring the lever 32 out of the path of the bightportion of the hook-like part 50, while the plug or plugs are rotated toeffect the required adjustment. The needle point bearing in this devicebeing coaxial with the body of the plunger in the plug 36, the bightpart need not be in a vertical plane, but may be inclined, and locatedeither above or below the axis of the part 42.

I claim:

1. A pressure indicating device comprising a sealed case, an elongatedtorsion member therein anchored at one end and free to rotate at itsother end around its longitudinal axis, a transverse lever fixed to thetorsion member approximately at said free end at right angles to saidaxis and having oppositely extended arms, aneroid chamber devicesmounted exteriorly of said case at opposite sides, slidingtorque-applying members mounted on the case movable approximately in theplane of rotation of said arms and each in a path across the position ofa respective one of said arms when said lever is at a given initialposition, and bearing against respective said arms from oppositedirections, operative connections between said aneroid devices andrespective said torque applying members, flexible diaphragm-like sealmeans forming parts of respective sides of said case around, andconnected centrally to said torque applying members, and exteriorlyvisible means to indicate angular positions or one at least of said armsrelative to the case.

2. A device of the character described comprising a hermetic case,external aneroid devices having terminal connection members mounted atopposite sides thereof, reciprocable on axes approximately in a commonplane and spaced from each other in said plane, said case including anelongated tubular extension on an axis in a plane normal to said firstnamed plane and to said axes of the terminal connection members, saidaxis of the extension being midway between said axes of the terminalconnection members, a rod-like elastic torsion member longitudinallyextended in said tubular extension, means to anchor one end of saidtorsion member at the outer end or" said extension, a rectilinear leverfixed at the opposite end of and at right angles to the axis of thetorsion member having oppositely extending arms normally in said secondnamed plane and across respective said axes of the terminal connectionmembers, reciprocating torque generating members mounted on the casemovable along said axes of said terminal connection members at oppositesides of the second named plane and connected between respective saidarms and terminal connection members in- Cir 5 eluding a low frictionmeans to seal the case at each such connection, and a duct connectioncommunicating with the interior of the case.

3. The structure of claim 2, wherein the said low friction meanscomprises a flexible sealing diaphragm forming part of the wall of thecase, and its central part included in said connection.

4. The structure of claim 3 wherein said diaphragm is mounted on a plugbody having screw engagement through the wall of the case, wherebyadjustment of the aneroids' relative to said lever may be etiected, saidtorque generating members consisting of point bearing plungers, saidarms having vertical radial flats receiving the points thereagainst.

5. The structure of claim 2 wherein said lever is formed with anindicator mark at the extremity of one of said arms, said case having awindow and transparent closure therefor adjacent the said extremity ofthe arm, and a fiducial mark on the case closely adjacent the path ofsaid first named mark under oscillation of the lever.

6. The structure of claim 5 wherein the said extremity of the lever armis formed with a surface substantially normal to the radius of the arm,cross hairs being marked thereon, one normal to the plane of oscillationof the lever, and the other aligned with this plane, said fiducial markincluding a line normal to the last named plane, and one coincident withthe direction of oscillation of said lever around the axis of thetorsion member.

7. The structure of claim 6 wherein the fiducial mark is positioned toalign with the said one hair at a predetermined zero position of thelever, and another positioned to align with the said other hair at apredetermined zero position of expansion and contraction of the rod.

8. The structure of claim 3 wherein means is provided for evacuatinggases from the interior of the case.

References Cited in the file of this patent UNITED STATES PATENTS

